TW201918740A - Lens and manufacturing method thereof - Google Patents

Abstract

A lens including a first lens group and a second lens group is provided. The first lens group is disposed between a magnified side and a minified side. The second lens group is disposed between the first lens group and the minified side. The lens includes six or less lenses, and at least four of the six or less lenses are aspherical lenses. The field of view of the lens between 100 degrees to 165 degrees, and the second lens group has at least one spherical lens.

Description

Lens and its manufacturing method

The present invention relates to an optical component and a method of fabricating the same, and more particularly to a lens and a method of fabricating the same.

With the advancement of modern video technology, video devices such as digital video cameras (DVCs) and digital cameras (DCs) have been widely used and widely used in various fields. One of the core components in these imaging devices is a lens for clearly imaging images onto a screen or a Charge Coupled Device (CCD). In addition, in recent years, smart home surveillance cameras have become more and more prosperous, and people are increasingly demanding thinner and optical performance. To meet the needs of such a lens, it is generally required to have a wide angle of view, miniaturization, thinning, high resolution, large aperture, low distortion, day and night confocal features.

However, in a general lens, it is necessary to have a switching filter device to achieve day and night confocal, or to increase the number of lenses in the lens to achieve day and night confocal. However, no matter which way, it will increase the production cost. In addition, in a general lens, a plurality of plastic lenses are used to reduce the cost, but the use of a plurality of plastic lenses has a large thermal drift phenomenon, resulting in a decrease in optical quality. Therefore, how to make a lens having the above characteristics and providing good optical quality is one of the important subjects of those skilled in the art.

Embodiments of the present invention relate to a lens having day and night confocal and good thermal drift performance and a method of fabricating the same.

An embodiment of the invention provides a lens including a first lens group and a second lens group. The first lens group is disposed between the image enlargement side and the image reduction side. The second lens group is disposed between the first lens group and the image reduction side. Wherein, the lens comprises six or less lenses, and at least four of the six or less lenses are aspherical lenses. The field of view of the lens is between 100 degrees and 165 degrees, and the second lens group has at least one spherical lens.

Based on the above, in the embodiment of the present invention, the design of the lens conforms to a preset condition standard, and thus the lens of the embodiment of the present invention can achieve a wide angle of view, miniaturization, day and night confocal, and low heat drift, and provides good Optical imaging quality.

The above described features and advantages of the invention will be apparent from the following description.

Fig. 1 is a schematic view showing a lens of an embodiment of the present invention. Referring to FIG. 1 , the lens 100 of the present embodiment includes a first lens group 110 and a second lens group 120 . The first lens group 110 is located between the image enlargement side OS and the image reduction side IS. The second lens group 120 is located between the first lens group 110 and the image reduction side IS. The first lens group 110 and the second lens group 120 are arranged along the optical axis A of the lens 100.

The lens 100 includes six or fewer lenses, and at least four of the six or less lenses are aspherical lenses. In the present embodiment, the lens 100 includes six lenses, and five of them are aspherical lenses. In this way, spherical aberration, coma aberration, astigmatism, curvature of field and distortion can be reduced, and the effect of high resolution can be achieved. In the present embodiment, the first lens group 110 has a negative refracting power, and the second lens group 120 has a positive refracting power. Further, in the present embodiment, the lens 100 includes at least four plastic lenses and does not have a cemented lens, and the second lens group 120 has at least one spherical lens.

In this embodiment, the first lens group 110 includes a first lens 112, a second lens 114, and a third lens 116 that are sequentially arranged from the image enlargement side OS to the image reduction side IS, and the second lens group 120 includes the slave image. The fourth lens 122, the fifth lens 124, and the sixth lens 126 are sequentially arranged on the magnification side OS toward the image reduction side IS. The first lens 112, the second lens 114, the third lens 116, the fourth lens 122, and the fifth lens 124 are aspherical lenses. In the present embodiment, the diopter of the first lens 112 to the sixth lens 126 are negative, negative, positive, positive, negative, and positive, respectively.

In this embodiment, the first lens 112 is a double concave lens, and the second lens 114 is a negative meniscus lens having a concave surface facing the image magnification side OS, and the third lens 116 has a orientation. a positive meniscus lens of the convex surface of the image magnifying side OS, the fourth lens 122 is a biconvex lens, the fifth lens 124 is a biconcave lens, and the sixth lens 126 is a biconcave lens. A lenticular lens.

Further, in the present embodiment, the lens 100 further includes an aperture stop S, a filter element 130, and a glass cover 140. The aperture stop S is disposed between the third lens 116 of the first lens group 110 and the fourth lens 122 of the second lens group 120. The filter element 130 is disposed between the sixth lens 126 of the second lens group 120 and the image reduction side IS. The glass cover 140 is disposed between the filter element 130 and the imaging surface 150 positioned on the image reduction side IS.

In the present embodiment, the lens 100 conforms to the condition of 100 degrees ≦ FOV ≦ 165 degrees, wherein the FOV is the field of view (FOV) of the lens 100, for example, in the diagonal direction of the imaging surface 150. Field angle. In this way, the lens 100 meeting the above conditions can ensure the optical imaging quality and have good optical characteristics.

The contents of Table 1 below will show the specific data of each lens in the lens 100 shown in FIG. (Table 1)

In Table 1, the pitch refers to the linear distance between the two adjacent surfaces along the optical axis A of the lens 100. For example, the pitch of the surface S1 is a linear distance between the surface S1 and the surface S2 and along the optical axis A. The corresponding thickness, refractive index and Abbe number of each lens in the annotation column should refer to the corresponding spacing, refractive index and Abbe number in the same column. Further, in Table 1, the surface S1 and the surface S2 are the two surfaces of the first lens 112. The surface S3 and the surface S4 are the two surfaces of the second lens 114, etc. and so on. The surface S7 is an aperture stop S. Surface S14 and surface S15 are the two surfaces of filter element 130. The surface S16 and the surface S17 are the two surfaces of the glass cover 140. The surface S18 is an imaging surface 150.

In the present embodiment, the surfaces S1, S2, S3, S4, S5, S6, S8, S9, S10, and S11 of the lens 100 are aspherical surfaces, and can be expressed by the following equation (1): (1)

In the equation, Z is the offset (sag) in the direction of the optical axis A, and c is the reciprocal of the radius of an osculating sphere, that is, the radius of curvature close to the optical axis A (for example, the surface S1 in Table 1) The reciprocal of the radius of curvature of S2, S3, S4, S5, S6, S8, S9, S10, and S11. K is a conic coefficient, r is an aspherical height, and A ₂ to A _{16 are} aspheric coefficients. In this embodiment, the coefficients K and A _{2 are both} zero. Table 2 below will list the aspheric parameter values of the surfaces S1, S2, S3, S4, S5, S6, S8, S9, S10, and S11. (Table 2)

In the lens 100 of the present embodiment, the total track length (TTL, the distance of S1 to S18 on the optical axis) = 15.9 mm. Effective focal length (EFL) = 2.00 mm. Aperture value (F-Number, Fno) = 2.0. The field of view angle FOV = 140 degrees.

2 to 6 are diagrams of imaging optical simulation data of the lens of Fig. 1. Please refer to FIG. 2 to FIG. 6 , wherein FIG. 2 is an optical transfer function ( MTF) of the lens 100 during the daytime, and the horizontal axis is the spatial frequency per cycle/mm (spatial frequency in Cycles per millimeter), the vertical axis is the modulus of the optical transfer function. In the present embodiment, the optical transfer function curve displayed by the lens 100 during the day is within the standard range, as shown in FIG.

3 is a graph of the optical transfer function of the lens 100 at an image height of 3.088 mm at night, with the horizontal axis being the spatial frequency and the vertical axis being the modulus of the optical transfer function. In the present embodiment, the optical transfer function curve displayed by the lens 100 at night is within the standard range, as shown in FIG. It can be verified that in the embodiment, the lens 100 can use fewer lenses and no need to switch the infrared filter without additional action, and can achieve day and night confocal without good use of glass bonding optical elements and has good daytime and nighttime. Optical imaging quality.

4, FIG. 5 and FIG. 6 are graphs of optical transfer functions of the lens 100 for different image heights at temperatures of 20 degrees Celsius, -20 degrees, and 80 degrees, respectively, the horizontal axis of which is the spatial frequency, and the vertical axis. For the modulus of the optical transfer function, T represents the curve in the meridional direction, S represents the curve in the sagittal direction, and the value after "TS" represents the image height, where the curve and arc in the meridional direction at an image height of 0.0000 mm The curves of the sagittal image coincide. In the present embodiment, the modulus of the optical transfer function of the lens 100 at a temperature of 20 degrees and at a spatial frequency of 63 lp/mm and an image height of 3.088 mm is greater than 60% at a temperature of -20 degrees. The modulus of the optical transfer function at a spatial frequency of 63 lp/mm and an image height of 3.088 mm is greater than 60%, and at a temperature of -20 degrees and at a spatial frequency of 63 lp/mm and an image height of 3.088 The modulus of the optical transfer function in mm is greater than 60%, as shown in Figures 4-6. Good optical performance at -20 degrees to 80 degrees at a spatial frequency of 63 lp/mm. In other words, the lens 100 of the present embodiment has low heat transfer and good optics when the temperature changes from -20 degrees Celsius to 80 degrees Celsius. Imaging quality.

FIG. 7 is a schematic diagram of a lens according to another embodiment of the present invention. Referring to FIG. 7 , the lens 200 of the present embodiment is similar to the lens 100 of FIG. 1 . The difference between the two is that in the embodiment, the second lens group 220 in the lens 200 includes an Abbe number greater than 70. Lens. Specifically, the Abbe number of the lens closest to the first lens group 210 in the second lens group 220 (ie, the fourth lens 122) is greater than 70. In this way, the chromatic aberration of the light of the visible light to the infrared light wavelength can be effectively reduced and the optical characteristics are good, and the lens 200 can achieve the effect that the focus position of the infrared light and the focus position of the visible light are substantially the same.

Specifically, the difference from the lens 100 in FIG. 1 is that, in the embodiment, the first lens 212 is a negative meniscus lens having a convex surface facing the image magnification side OS, and the second lens 214 is a The double concave lens, the third lens 216 is a lenticular lens. The first lens 212, the second lens 214, the third lens 216, the fifth lens 124, and the sixth lens 126 are aspherical lenses.

The contents of Table 3 below will show the specific data of each lens in the lens 200 shown in FIG. (table 3)

The meanings of the surface S1 to the surface S18 described in the comment column of Table 3, and the described pitch, refractive index, and Abbe number are the same as those of the corresponding pitch, refractive index, and Abbe number in the same column. The reference mode of Table 1 will not be repeated here.

In the present embodiment, the surfaces S1, S2, S3, S4, S5, S6, S10, S11, S12, and S13 of the lens 200 are aspherical surfaces, and can be expressed by the above equation (1). Among them, in the present embodiment, the coefficients A ₂ and A _{12 are} zero. Table 4 below will list the aspheric parameter values of the surfaces S1, S2, S3, S4, S5, S6, S10, S11, S12, and S13. (Table 4)

In the lens 200 of the present embodiment, the total length of the lens is 16.1 mm. The effective focal length is 1.85 mm. The aperture value is 2.0. The field of view is 140 degrees.

FIG. 8 is a schematic diagram of a lens according to another embodiment of the present invention. Referring to FIG. 8 , the lens 300 of the present embodiment is similar to the lens 200 of FIG. 7 . The difference between the two is that the number of lenses in the first lens group 310 of the lens 300 is two, and the lens in the second lens group 320 is The number is three. Specifically, in the present embodiment, the lens 300 includes five lenses.

Specifically, the difference from the lens 200 in FIG. 2 is that, in the embodiment, the first lens group 310 includes the first lens 212 and the second lens which are sequentially arranged from the image enlargement side OS to the image reduction side IS. 314, and the second lens group 320 includes a third lens 322, a fourth lens 324, and a fifth lens 326 which are sequentially arranged from the image enlargement side OS to the image reduction side IS.

In detail, in the embodiment, the second lens 314 is a positive meniscus lens having a concave surface facing the image magnification side OS, the third lens 322 is a lenticular lens, and the fourth lens 324 has an orientation image. A negative meniscus lens that magnifies the convex surface of the side OS, and the fifth lens 326 is a lenticular lens. The first lens 212, the second lens 314, the fourth lens 324, and the fifth lens 326 are aspherical lenses. In the present embodiment, the diopter of the first lens 212 to the fifth lens 326 are negative, positive, positive, negative, and positive, respectively.

The contents of Table 3 below will show the specific data about each lens in the lens 300 shown in FIG. (table 5)

In Table 5, the surface S5 is the aperture stop S. Further, the meanings of the surfaces S1 to S16 described in the column of the table in Table 5, and the values of the pitches, refractive indices, and Abbe numbers described in the same column, the corresponding pitches, refractive indices, and Abbe numbers in the same column are referred to. The manner is the same as that of Table 1, and will not be described here.

In the present embodiment, the surfaces S1, S2, S3, S4, S8, S9, S10, and S11 of the lens 300 are aspherical surfaces, and can be expressed by the above equation (1). Among them, in the present embodiment, the coefficient A ₂ is zero. Table 6 below will list the aspheric parameter values of the surfaces S1, S2, S3, S4, S8, S9, S10, and S11. (Table 6)

In the lens 300 of the present embodiment, the total length of the lens is 16.1 mm. The effective focal length is 1.92 mm. The aperture value is 2.0. The field of view is 140 degrees. The lenses 200, 300 are similar to the lens 100 of FIG. 1, and can use fewer lenses and no additional action to switch the infrared filter, and can achieve good daytime and nighttime optical imaging quality without using glass bonding optical components. That is to say, the lenses 200, 300 can reach day and night confocal. In addition, the lenses 200, 300 also have low heat transfer and good optical imaging quality.

Fig. 9 is a flow chart showing a method of manufacturing a lens according to an embodiment of the present invention. Referring to FIG. 9, in the present embodiment, the manufacturing method of the lens can be applied to at least the lens 100 of FIG. 1, the lens 200 of FIG. 7, or the lens 300 of FIG. The following description will be made by taking the lens 100 of FIG. 1 as an example, but the invention is not limited thereto. In the manufacturing method of the lens of this embodiment, in step S900, a lens barrel is provided. In step S910, the first lens group 110 is placed and fixed in the lens barrel. In step S920, the second lens group 120 is placed and fixed in the lens barrel to complete the manufacture of the lens 100.

In summary, in the exemplary embodiment of the present invention, the design of the lens conforms to a preset condition standard, and thus the lens of the embodiment of the present invention can achieve a wide angle of view, miniaturization, day and night confocal, and low heat drift, and Provides good optical imaging quality.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100, 200, 300‧‧‧ lens

110, 210, 310‧‧‧ first lens group

112, 212‧‧‧ first lens

114, 214, 314‧‧‧ second lens

116, 216, 322‧‧‧ third lens

120, 220, 320‧‧‧ second lens group

122, 324‧‧‧ fourth lens

124, 326‧‧‧ fifth lens

126‧‧‧ sixth lens

130‧‧‧Filter elements

140‧‧‧glass cover

150‧‧‧ imaging surface

A‧‧‧ optical axis

OS‧‧‧ image magnification side

IS‧‧‧Image reduction side

S‧‧‧ aperture diaphragm

S1~S18‧‧‧ surface

FIG. 1 is a schematic diagram of a lens according to an embodiment of the present invention. 2 to 6 are diagrams of imaging optical simulation data of the lens of Fig. 1. FIG. 7 is a schematic diagram of a lens according to another embodiment of the present invention. FIG. 8 is a schematic diagram of a lens according to another embodiment of the present invention. Fig. 9 is a flow chart showing a method of manufacturing a lens according to an embodiment of the present invention.

Claims (12)

A lens comprising: a first lens group disposed between an image magnification side and an image reduction side; and a second lens group disposed between the first lens group and the image reduction side, wherein the lens The lens includes six or less lenses, at least four of the six or lower lenses being aspherical lenses having an angle of view between 100 degrees and 165 degrees, and the second lens group having at least one spherical surface lens. A lens comprising: a first lens group disposed between an image magnification side and an image reduction side; and a second lens group disposed between the first lens group and the image reduction side, wherein the lens The lens includes six or less lenses, at least four of the six or less lenses are aspherical lenses, the angle of view of the lens is between 100 degrees and 165 degrees, and the second lens group includes an abe A lens with a number greater than 70. The lens of any one of claims 1 to 2, wherein the lens further comprises an aperture stop disposed between the first lens group and the second lens group. The lens of any one of claims 1 to 2, wherein the first lens group has a negative refracting power and the second lens group has a positive refracting power. The lens of any one of claims 1 to 2, wherein the first lens group comprises a first lens, a second lens and a first order from the image enlargement side to the image reduction side. a third lens, the second lens group includes a fourth lens, a fifth lens and a sixth lens arranged in sequence from the image enlargement side to the image reduction side, and the fourth lens and the fifth lens are Aspherical lens. The lens of claim 5, wherein the lens further satisfies one of the following conditions: (1) the diopter of the first lens to the sixth lens are negative, negative, positive, positive, negative, respectively. (2) The first lens, the second lens, and the third lens are aspherical lenses. The lens of any one of claims 1 to 2, wherein the lens further satisfies one of the following conditions: (1) includes at least four plastic lenses, and the lens does not have a cemented lens; (2) The Abbe number of the lens closest to the first lens group among the second lens groups is greater than 70. The lens of claim 2, wherein the number of lenses in the lens is six, and wherein the fourth lens from the image enlargement side to the image reduction side is a spherical lens and is closest to the image. The lens on the reduction side is an aspherical lens. The lens of claim 2, wherein the number of lenses in the first lens group is two, and the number of lenses in the second lens group is three. The lens of claim 9, wherein the first lens group comprises a first lens and a second lens arranged in sequence from the image enlargement side to the image reduction side, the second lens group comprising The image magnifying side is a third lens, a fourth lens and a fifth lens arranged in sequence on the image reducing side, wherein the fourth lens and the fifth lens are aspherical lenses. The lens of claim 10, wherein the lens further satisfies one of the following conditions: (1) the diopter of the first lens to the fifth lens are negative, positive, positive, negative, and positive, respectively; (2) The first lens and the second lens are aspherical lenses. A lens manufacturing method comprising: providing a lens barrel; placing and fixing a first lens group in the lens barrel; and placing and fixing a second lens group in the lens barrel, wherein the lens Including six or less lenses, at least four of the six or lower lenses are aspherical lenses having an angle of view between 100 degrees and 165 degrees, and the second lens group has at least one spherical lens .